/usr/share/doc/perl-prefork-1.04/README

NAME
prefork - Optimized module loading for forking or non-forking processes
SYNOPSIS
In a module that normally delays module loading with require
# Module Foo::Bar only uses This::That 25% of the time.
# We want to preload in in forking scenarios (like mod_perl), but
# we want to delay loading in non-forking scenarios (like CGI)
use prefork 'This::That';
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